Novel notions of zero injection property of buses in optimal PMU location with efficient observability enhancement focusing on security concepts

In this paper, a new method is proposed for security-oriented, optimal placement of phasor measurement units (PMUs) incorporating efficient observability redundancy. In this way, novel concepts in zero-injection buses (ZIBs) are introduced. The proposed concepts regard aspects of the ZIBs effect that have not yet been studied; thus, by applying this concept, maximum possible capacity of the ZIBs will be available for use. Therefore, the proposed method is capable of producing optimum possible results with tangibly higher ZIBs capacity usage and measurement redundancy levels than those reached in preceding works. In addition, the reliability of fragile areas monitoring from overvoltage viewpoint is enhanced. Considering the fact that complete synchronized network observability is undeniably significant for making control decision in critical conditions to avoid brownouts or blackouts, a novel practical framework is proposed based on backup observability concept in order to model branch outage in addition to PMU loss and channel failure. All proposed security models can be tested by practical, large-scale test systems such as Polish 2383- and 3375-bus. Also, in the case of branch outage, selective security criteria are considered so as to enhance security of network observability against cascading failures in electric power systems.